Elihu thomson



(No Mode l.)

E. THOMSON.

DYNAMC ELECTRIC MACHINE.

No. 269.605. Patented Deo.26,1882.

,HN Y P -Fll-W/ Figa P r P fz B2 P ICL-3 INVENTUH:

MltlNiTnD STATES PATENT Fries.,

ELIHU THOMSON, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO THE AMERICAN ELECTRIC COMPANY, OF SAME PLACE.

DYNAMO-ELECTRIC MACHINE.

SPECIFICATION forming part of Letters Patent No. 269,605, dated December 26, 1882,

Application filed September 1S, 18822. (No model.)

- Britain, in the county of Hartford' and State of Connecticut, haveinvented certain new and useful Improvements in'Dynamo-Electric Mach1nes,of which the following is a specilication.

The object of my invention is to prevent the wear and destruction of the commutators of dynamo-electric machines, caused by the spark or flash which occurs when the brushes or collectors of the machine pass from one commututor plate or segment to a succeeding one.

My invention'consists in the employment of condensersurfaces connected to the coil-terminals of the armature, as hereinafter described.

In the accompanyingdrawingsIhave shown my invention as applied to what is known as a three-coilarmature machine,770f the general type shown in Letters Patent of the United States No. 223,557, dated January 13, 1880, and No. 233,047, October 5,1880; butin showing the invention in connection with this class of machines I do not wish to be understood aslimitinginyselftosuch an application thereof, and the same arrangement of condensersurfaces and connections may be used with other kinds ot' dynamo-electric or magnetoelectric machines, having al greater or less number of armature-coils and commutatorsegments, or even with electric motors, the terminals of the coils that are connected to the commutator plates or segments of said motors being placed in electric connection with separatejcondenser surfaces or plates, as herein set forth with reference to dynamo -electric machines.

In the accompanying drawings, Figure 1 is a vertical longitudinal section of an armaturecarrier or structure for a three-coil spherical armature of the same general forni as is described in Patent No. 233,047. This ligure shows my condenser attachment N in place upon the armature-shaft. Fig. 2 is an end view ofthe armature. Fig. 3 is adiagram view, illustrating the manner in which the armaturecoils, commutator, and condenser are connected to one another. Fig.4tillust1atesa modified arrangement, in which a supplemental commutator is used in connection with the regular commutator and condenser. Fig. 5 shows a construction whereby the condenser may be stationary while the armaturecoils and commntator revolve. t

Referring to Fig. 1, G G indicate circular plates or frames ot' iron, which are suitably mounted upon and secured to the shaft S ot' the machine. Extending from one to the other of these plates is a series of separate bridges of any suitable material, two of which are shown at I I, and which serve to support iron wire wound on the exterior, as shown, so as to give to the whole the form of an oblate spheroid. Projecting pins P P are inserted at suitable intervals as guides in winding the insulated wire, which latter, when the armature is complete, gives to said armature the form shown by dotted lines. At each end there surrounds the shaft Sa series of strips, R R, preferably of an insulating material, leaving flutings o'r grooves around the shaft. These flutvings or grooves might be formed in the shaft itself in the process of manufacture, the strips or ribs R R being integral with the'shaft. This construction ot' armatnre-carrier is contained in prior applications for patent tiled by me, and no special claim is herein made to it.

N represents a box supported on the shaft in any suitable manner, and containing a condenser with connections t 't 't from its inclosed plates, to which connections the armature-coils are joined in amanner that will be presently described.

In Fig. 2 the armature-coils B B2 B are seen to lie around the ribs R in such manner as to leave open air-spaces around the shaft. When the armature is revolved lair enters at these points, and is ejected through the coils, where they overlap, by numerous small airchannels that invariably exist, and greatly promotes the cooling` of the armature. There are twelve projections P P, &c.,dividing and guiding the coils.

Fig. 3 shows the arrangement ofconnections of armature-coils, commutator, and condenser. The parts are shown separated for clearness. The armature-coils B B2 B3 are ljoined at J, and their other terminals are, as usual in inachines constructed according tothe plans patented to lne, connected respectively to the seg- IOO ments of a three-segment commutator, K' K2 K2, mounted on the shaft S. These segments are also connected, in the manner shown, to surfaces m' m2 m2, of tin-foil or other suitable material, having the usual interposed insulator, and forming altogether a condenser, N, mounted by preference upon the armatureshaft, and having three independent sets ot' condenser-plates, (built up symmetrically inthe we1l-known way,) instead ot the two sets ordinarily employed, the combined plates ct' each set, m', or m2, or on, representing` about ten square feet (more or less) ot' active surface. The size ot the condenser-surface will, however, vary with the size et' the machine and the nature and strength ofthe spark which it is desired to suppress. With the arrangement of' eondensing-surfaces described the spark at the coinmutator may be made to almost entirely disappear, in virtue of the condensersurt'aces being always ready to receive and condense or absorb any residuum ot' current which might make its appearance at the slots in the commutator when passing the collecting-brushes.

In Fig. 4t a still more complete device employing the same parts is shown. rI he coils 3' B2 B2 are connected as before, at one end,

J, and separately to the three segments K' K2 K3 ofthe commutator. The condenser in this case has six independent foil surfaces, (instead ol' the three foil surfaces or sets of foil suri'aces shown in Fig. 3,) insulated and used in three pairs-thatis, it is virtually three condensers, each having two opposed foils or plates. Uomnmtatorsegment K' is connected to one foil or sur-tace ot' a condenser, the other or opposed foil or. surface of which is connected to a corresponding segment, L', in a secondary commutator. Again, K2 is connected to one surface otl another condenser, the opposed surface to which is connected to L2. In like manner K8 of the primary com mutator and L3 ot' the secondary commutator are connected to the two poles or opposed surface ofthe third condenser. rthere is, under these conditions, no metallic connection trom K' to L', K2 to L2, or K3 to L, but they are, as it were, inductively connected on account ot their condenser-foils being respectively opposed. Whatever electrical impulse appears in K', K2, or K2 is retlected also in L' L2 L3, respectively. The cominutator-brushes applied to K' K2 Ks are two connected pairs, Y' W' and V2 W2, respectively, which occupy different angular' Apositions, as shown. A pair ot brushes, U' and U2, bear on the secondary commutator L' L2 L2 at opposite points, and are singly connected to the other commutator-brushes, U' to Y' and W', and U2 to V2 and W2 The several brushes are so set that the slots between the segments of the commutator K' K2 KS shall slightly precede those in L' L2 L3 when leaving the tips oit the brushes. This condition is shown in the figure where the slot between K2 and K3 has justpassed the brush V', while that between the corresponding segments, L2 and L2, is at the same moment just under the brush U'. Under these circumstances very little spark is produced at the slots in the com inutator-segments K' K2 K2; but the current that would produce it goes to the condenser and is absorbed, whilea mon'ientary e'lllux otl current from the secondary commutator takes place. These currents are joined together and carried through the held-magnet coils C U and light or other resistance (t. v

In Fig. 3 the condenser X is shown as revolving` with the shaft; but this is not essential. ]Jig. 5 shows it stationary. In this case three rings, i" yr2 r2, mounted on the shat't and insulated from cile another, are connected respectively with the segments K' K2 K2 ot' thecommutator. Upon the rings i" r2 r2 bear brushes y y2 Uf?, separately connected to the condenser-teils. rlhe action ot' this arrangement is precisely the same as that ot' Fie. 3.

My invention may be carried into ett'ect by the employment ot' any desired construction ot' condenser. Said condenser may be mounted and connected to the armature coil-terminals in other ways or by other means besides those herein shown without departing from the invention.

l. The combination, with a dynamo-electric machine, ot a condenser the separate foils or surfaces ot' which are continuously connected to separate segments ot' the cominutator.

2. The combination, with a dynamo-electric machine, ot a condenser mounted upon the armature-shaft and connected to the commutator-segments in the manner described.

3. As a spark-absorber in a dynamo-elec tric machine, a set of conderisingsurfaces in continuous connection with terminals ot' the armature'coils, and com mutator-segments connected to said terminals, respectively.

et. The combination, in a dynamo-electric machine, ol an armature having three coils' united in a common ljoint or electrical connection, J, a three-segment commutator, to the segments ot' which the free ends ot' the coils are respectively connected, and a condenser connected to the segments in the manner described.

5. rlhc combination, with a dynamoelectric machine, ot' a condenser consisting ot' a number ot' pairs or sets of condensing surfaces or plates, connected in the manner described to the separate segments ot' the primary or main comm utator and to the segments of a secondary or supplemental commutator.

t5. The combination, with a three-coil armature, ot'a primary or main three-segment commutator, a secondary three-segment commutator, a pair ot' condensing surfaces or plates induetively uniting the corresponding` segments ot' the two commutators, and electrical connections t'rom the brushes ot' the primary to the brushes ofthe secondary com mutator.

7. In a dynamo-electric machine, the combination, substantially as described, ot' a primary and a secondary com muta-tor ind uctively IOO IIO

united through the plates or foils ot' a eon- Signed at Ne\vBritain,in thecountyof Hartdenser, and arranged with relation to one anford and State of Connecticut, this 12th day ot' other so that their segments shall leave their September, A. D. 1882. brushes-the segments of one colnmutator 5 slightlyin advance of those of the other. ELlHU THOMSON.

S. The combination, with a dynamo-electric machine, ot' a condenser the separate foils or Witnesses: surfaces of which are in continuous electrical E. WILBUR RICE, connection with the separate terminals ofthe ROBT. B. HAINES, Jr. 1o armature, as and for the purpose described. 

